When I watched the Joe Cocker band around 40 years ago they had 2 guitarist's playing Telecasters who took turns having full change overs, every other song! I expect as they were sweating so much and playing so hard that to avoid tone loss and breakages.
Pro guitarist's will change their strings before each gig, but they all have a guitar technician.
Jim, I change strings when they become dirty or lose tone. I must say that your guitar has a lovely tone even though they are several years old.